Some pulsed laser energy transmitting catheters currently used for ablating and clearing blockages in human arteries may use a single large diameter fiber optic which tends to be stiff for some such indications. For improved catheter flexibility, multiple smaller diameter fiber optics may be used which are arranged in various shaped bundles. In some cases, excimer laser ablation efficiency of atheroma may be inversely proportional to the relative amount of inactive surface area or dead space at the ablation catheter tip contacting the target surface being ablated. Multiple fiber optic based catheters may have a significant amount of dead space, which may be due to the cladding, buffer, fiber packing factor, glue and the sidewall of the catheter outside tubing along with a guidewire lumen tubing or the like.
A doctoral thesis by Hamburger showed ablation histology for multiple fiber optic bundle ablation catheters versus a single fiber optic and indicated that the dead space leads to more tissue damage and less efficient ablation than a window tip with a homogenous energy distribution ablating surface, “New Aspects of Excimer Laser Coronary Angioplasty Physical Aspects and Clinical Results, printed by Optima Grafische Communicatie ISBN 90-73235-27-8, Rotterdam, Jaap N. Hamburger, 1999. Hamburger's conclusions stated that: “Optimization of excimer laser coronary angioplasty can be achieved by elimination of ultraviolet-absorbing media, reduction of catheter advancement speeds and by reduction of the non-light emitting area at the tip of a laser catheter.” What are needed are catheter device configurations and methods for use thereof which allow for increased optical beam expansion of the optical beam which exits the distal portion of the catheter and which reduce dead space due to catheter elements which encompass an optical window at a distal portion of a laser catheter.